David Díaz (born June 7, 1976) is an American former professional boxer who competed from 1996 to 2011, and held the WBC lightweight title from 2007 to 2008.
Diaz defeated Mexican legend Erik Morales on August 4, 2007, by a controversial unanimous decision to defend his title.
On March 13, 2010, Diaz challenged Humberto Soto for his old WBC lightweight title, which had recently been vacated by Edwin Valero, on the undercard of Pacquiao's fight with Joshua Clottey.
Soto defeated Diaz, dropping him in the opening and closing rounds, en route to a unanimous decision victory.
Earlier in that very same year on February 28, 2013, Diaz endorsed friend and former boxer Bill Evans as a candidate for Cook County Sheriff in 2014.